According to a known design, the end of the driving shaft comprises a conical section, the surface of which is provided with a series of raised catches which extend parallel to the axis, and a threaded end section.
The conical section is mounted in a recess having a complementary profile, with a smooth wall, formed in the driving head whereas the threaded end protrudes above the upper face of the driving head in order to be screwed into a clamping nut, the annular clamping face of which cooperates with the upper face of the driving head.
The clamping operation in the assembled position of the driving head due to the nut has the effect of causing penetration of the catches into the material forming the wall of the conical recess of the driving head.
The clamping force applied to the nut causes progressive penetration of the catches into the driving head and the catches become impressed into the wall in order to form the rotational driving means of the driving head by the motor shaft.
This particularly simple design has the drawback of varying the axial position of the driving head on the motor shaft as a function of the value of the clamping force, i.e. it does not enable a precise dimension of the driving head in relation to the motor shaft, and therefore in relation to the pane of glass to be wiped, to be determined.
The object of the present invention is to propose a new design of such a windscreen wider device which enables this drawback to be removed.